湿地中的藻类生态学研究进展

从湿地中藻类的种群结构、藻类在湿地中的功能、湿地中的藻类生产力及其影响因素等方面综述了天然湿地中的藻类生态学研究进展．湿地植物区系主要有附泥藻类、附植藻类、后周丛藻类和浮游植物4种类型,其中常见的是附泥藻类的硅藻、绿藻和蓝藻．藻类最显著的作用是作为湿地食物网中的初级生产者,也作为湿地环境污染的生物指示物．影响藻类生产力的因素有水力学因素、营养、温度、光、大型植物及草食动物和其它动物．未来对藻类的研究应侧重于湿地藻类生物多样性、藻类生物量、生产力、种群组成的环境控制及其相互关系,以及藻类作为水环境及湿地污染程度指标的研究,“基因治藻”也将是未来研究的新方向．     

Hydrogen peroxide induces the activation of the phospholipase C-γ1 survival pathway in PC12 cells： protective role in apoptosis

It has been reported that phospholipase C-γ1 （PLC-γ1） plays an important protective role in hydrogen peroxide （H2O2）-induced pheochromocytoma （PC） 12 cells death. However, most studies have used high doses of H2O2 and the downstream targets of PLC-γ1 activation remain to be identified. The present study was designed to examine the roles of PLC-γ1 signaling pathway in the apoptosis of PC12 cells induced by low dose of H2O2, as well as the downstream factors involved in this pathway. Low-dose treatment of H2O2 resulted in PLC-γ1 tyrosine phosphorylation in a time-dependent manner and H2O2 killed the PC12 cells by inducing necrosis. In contrast, pretreatment of PCI2 cells with U73122, a specific inhibitor of PLC, markedly increased the percentage of dead cells. The mode of cell death was converted to apoptosis as determined by Hoechst/PI nuclear staining and fluorescence microscopy. Western blot analysis demonstrated that the expression of Bcl-2 protein and the activation of pro-caspase-3 were not significantly affected by low dose of H2O2 alone. However, after pretreatment with U73122, Bcl-2 protein expression was dramatically decreased and the activation of pro-caspase-3 was significantly increased. We concluded that PLC-γ1 plays an important protective role in H2O2-induced PC12 cells death. Bcl-2 and caspase-3 probably participate in the signaling pathway as downstream factors.     

Isolation and characterization of microsatellite loci in Babylonia areolata and cross-species amplification in Babylonia formosae habei

Nine novel microsatellite primer pairs were presented for Babylonia areolata, representing the first microsatellite markers available for this genus. Levels of polymorphism were variable with 2 to 11 alleles per locus and expected heterozygosities ranging from 0.073 to 0.907 in 27 individuals of the population from which the loci were isolated. We found significant heterozygote deficit at one locus that might be attributable to null alleles. We were successful at cross-amplifying six loci in the congeneric B. formosae habei. These markers are therefore potentially useful for conservation studies, population structure assessment, ecological analyses and linkage map construction.     

Winter foraging habitat selection of brown-eared pheasant (Crossoptilon mantchuricum) and the common pheasant (Phasianus colchicus) in Huanglong Mountains, Shaanxi Province

The foraging habitat selections of brown-eared pheasant (Crossoptilon mantchuricum) and the common pheasant (Phasianus colchicus) were studied in Huanglongshan Nature Reserve Shaanxi, China. Foraging habitat characteristics were measured on the basis of expected differences between species at 183 sites from November to December 2006 and January 2007. The results showed that both species selected foraging habitats with altitude (<1200 m), conifer forest, half sunny and half shady slope, sunny slope, density of trees (<5 individuals/100 m²), cover of shrub (>50%), visibility class (<10%) and distance to water source (<300 m). However, the brown-eared pheasant selected habitats with cover of trees (30–50%), middle or lower slope location, distance to edge of woods (<300 m) and human disturbance (<500 m), and the selection on density of shrub was not observed, compared to the selections on cover of trees (<30%), lower slope location, distance to edge of woods (<500 m) and human disturbance (<300 m), and density of shrub (>500 individuals/100 m²) for common pheasant. We also found that the common pheasant avoid predators by concealment whereas brown-eared pheasant evade predations by running away strategy.     

Potential Autonomous Selfing in Gesneria citrina （Gesneriaceae）, a Specialized Hummingbird Pollinated Species with Variable Expression of Herkogamy

Species with mixed mating systems often demonstrate variable expression of breeding system characteristics and thus represent the opportunity to understand the factors and mechanisms that promote both outcrossed and selfed seed production. Here, we investigate variation in levels of herkogamy （variation in stigma-anther separation distance） in a Puerto Rican population of hummingbird pollinated Gesneria citrina Urban. There is significant variation in herkogamy levels among individuals of this species and stigma-anther separation is negatively associated with the ability to set fruits and seeds in the absence of pollinators. The variation in levels of herkogamy may represent a mechanism to ensure the production of some self-fertilized progeny in the absence of hummingbird pollinators. We also describe a novel breeding system in G. citrina, where stamens elongate over time to reach stigma height, but stamen elongation is accelerated by pollination. These results suggest that once the flowers are pollinated, stamen elongation may favor increased pollen removal and siring success, while the reduction in stigma-anther distance no longer imposes the risk of interference between male and female functions. We discuss our findings of breeding system variation in the context of pollination system evolution in an island setting （Antillean islands）.     

TRPC1 protects dopaminergic SH-SY5Y cells from MPP＋, salsolinol,and N-methyl-（R）-salsolinol-induced cytotoxicity

Neurotoxins and alterations in Ca2＋ homeostasis have been associated with Parkinson＇s disease （PD）, but the role of store-operated Ca2＋ entry channels is not well understood. Previous studies have shown the neurotoxicity of salsolinol and 1-methyl-4-phenylpyridinium ion on SH-SY5Y cells and cytoprotection induced by transient receptor potential protein 1 （TRPC1）. In the present study, N-methyl-（R）-salsolinol was tested for its cellular toxicity and effects on TRPC1 expression. MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-dipbenyl- tetrazolium bromide） assays, DAPI （4＇,6-diamidino-2-pheny- lindole）, fluorescein isothiocyanate-Annexin-V/propidium iodide, western blot analysis, and JC-1 labeling revealed that the three indicated drugs could induce caspase-dependent, mitochondrial-mediated apoptosis. Exposure of SH-SY5Y cells to the indicated drugs resulted in a significant decrease in thapsigargin-mediated Ca2＋ influx and TRPC1 expression. Immnnocytochemistry experiments revealed that neurotoxins treatment induced TRPC1 translocation to the cytoplasm. Taken together, our results indicate that treatment with neurotoxins may alter Ca2＋ homeostasis and induce mitochondrial-mediated caspase-dependent cytotoxicity, an important characteristic of PD.     

A cquired Cardiomyopathy Caused by Cardiac Tsc1 Defi ciency简

Cardiomyopathies are myocardial disorders with enlarged, thick, or rigid cardiac muscles. Because no effective treatment is available to prevent the deterioration of the myocardium function, the prognosis of cardiomyopathy is usually poor. Cardiomyopathies can be inherited or acquired. A number of genes associated with inherited cardiomyopathy, such as the genes encoding for sarcomeric, cytoskeletal,     

Study on coastal wetland habitat quality evaluation in Quanzhou Bay, Fujian, China

Coastal wetland is located in the active interface between land and sea, which is one of the richest biodiversity habitats, while it is seriously disturbed and destroyed by anthropogenic activities in both terrestrial and marine parts. Habitat serves as the basis for organism survival, providing food, shelter, water, space and so on, and habitat degradation and loss caused by intense anthropogenic activities is widely considered as the main reason for biodiversity decline and loss. However, there is still limited study on the evaluating methods of coastal wetland habitats, especially for those in a large scale. In this study, methods for evaluating coastal wetland habitat quality, including selecting indicators, setting value assignment criteria and weights were discussed systematically, a method of coastal wetland habitat quality evaluation was established, and the habitat quality in Quanzhou Bay was also evaluated as a case study. The present study provided a new concept and method to assess quantitatively habitat status, indicate the ecological status and its change, and also reflect and predict indirectly the ecological impact of human activities.
Referring to the habitat evaluation system (HES) developed by United States in the mid 1970s, the evaluation method was established by thorough analysis of the characteristics of coastal wetland. The habitat indicators were selected in terms of three habitat factors as follows: chemical factors, including dissolved oxygen (DO), phosphate in seawater, sulfide in sediment, and regional priority pollutants; physical factors, including landscape naturalness index and coastline artificialization index; biological factors, including invasive species risk and area ratio of invasive alien species. Weights were established by Analytic Hierarchy Process, combined with several-round expert evaluation. Evaluation criteria providing principles for value assignment of each indicator, were established referring to previous standards and related researches. The final result for assessing habitat quality was indicated and stated by the value of Habitat Quality Index (HQI), which is the weighted sum of each indicator. Habitat quality increased with the HQI value, with value ranging from 0 to 100.
The established evaluating method was applied to assess the habitat quality of Quanzhou Bay, located in the southeast coastal zone of Fujian Province, with a total area of 136.4 km², which is an important bay in Fujian. Quanzhou Bay wetland is a typical coastal wetland with diverse wetland habitats, including mangrove, estuary, island, aquaculture ponds, salt pan, shallow sea, mud flat and so on. The Quanzhou Bay is now seriously suffering environmental problems, e.g. eutrophication due to great discharge of domestic, agricultural and industrial wastewater, rapid urbanization and reclamation resulting in decreased wetland area, and the invasion of alien species. The evaluation results showed that the habitat quality index value was 68.13, 57.99 and 51.23 in 1989, 2002 and 2008, respectively, indicating that the habitat degraded gradually. The five major factors that led to decline of HQI value were phosphate in seawater, lead in sediment, landscape naturalness index and coastline artificialization index and area ratio of invasive alien species. Therefore, in order to improve and maintain habitat quality, it is urgent to control pollution, large-scale reclamation and Spartina invasion in Quzhou Bay.